Effect of moving-orientation of the piezoelectric fan on thermal characteristics of the concave surfaces with different curvature

The present work aims at numerically investigating on the flow and heat transfer performances induced by vibrating piezoelectric fan for cooling heated concave surfaces. Two main relevant parameters, relative curvature (K) of concave surface and moving-orientation of the piezoelectric fan, are taken into consideration. The relative curvature (K) is varied from 0.01 to 0.25. The moving-orientations of the piezoelectric fan include transverse oscillation and axial oscillation. The influence mechanism of these parameters are analyzed in terms of the time-averaged heat transfer coefficient, instantaneous streamlines and isosurface of lambda(2). The heat transfer results indicate that the axial oscillation is more favorable for improving the heat transfer performance than the transverse oscillation, especially in the zone near the fan vibration envelope. Meanwhile, the flow field reveals that the relative curvature of the concave surfaces influences the flow feature under longitudinal configuration substantially. (C) 2022 Elsevier Ltd. All rights reserved.